Forced to Close bank account

I called on 31st after cancelling my contract mid December as it has now expired. First call on the morning of 31st/12/2014, I spent all day on the phone trying to resolve an issue. I called on 2nd/01/2015 to explain why I would also like to make payment arrangements & was advised that someone would call me back in 2 days. This didn't happen. It took me several phone calls to get to the Legal dept as I wanted to make payment arrangements for the final part of my account. Finally made the arrangements to pay in two parts (half by end Jan & half by end Feb).. I paid half on 17th Jan, was debited other amounts 3 or 4 times (which cost me for each reversal & cancelled by email and faxed doc's through didn't help). By this time I had ref. no's & case no's coming out of my ears, spent about 6 days of TIME on the phone. Called again to prevent another debit order when making 2nd payment, another amount had to be reversed which forced me to close my bank account. I was handed over in 2nd week of Feb been to be black listed. Why? I paid as per arrangement with Legal department. To this day - the legal, contract and accounts dept don't talk to each other.